From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id mB5CIpXq013384 for ; Fri, 5 Dec 2008 06:18:53 -0600 Received: from one.firstfloor.org (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 197AC16B5797 for ; Fri, 5 Dec 2008 04:18:50 -0800 (PST) Received: from one.firstfloor.org (one.firstfloor.org [213.235.205.2]) by cuda.sgi.com with ESMTP id M3ZaQJtaQTeGgYRn for ; Fri, 05 Dec 2008 04:18:50 -0800 (PST) Date: Fri, 5 Dec 2008 13:29:30 +0100 From: Andi Kleen Subject: Re: Device loses barrier support (was: Fixed patch for simple barriers.) Message-ID: <20081205122930.GB6703@one.firstfloor.org> References: <20081204145810.GR6703@one.firstfloor.org> <20081204174838.GS6703@one.firstfloor.org> <20081204221551.GV6703@one.firstfloor.org> <20081205004849.GX6703@one.firstfloor.org> <20081205013739.GZ6703@one.firstfloor.org> <20081205115225.13c277ee@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Disposition: inline In-Reply-To: <20081205115225.13c277ee@lxorguk.ukuu.org.uk> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Alan Cox Cc: Andi Kleen , linux-kernel@vger.kernel.org, xfs@oss.sgi.com, Andi Kleen , Mikulas Patocka , Alasdair G Kergon , Milan Broz > Not when the fundamental design of the code is broken and trashes > performance. Sorry but that's just not correct. There's nothing in late failing barriers that "trashes performance". The file system writers have to be careful to handle it, but at least the current ones all do. And also if someone writes a hypothetical fully asynchronously driven barrier based IO transaction system it would be still possible to handle the late failing barrier without too many complications. Also late failing barriers is pretty much the only sane way to implement barriers in software remapping schemes like DM and MD. -Andi -- ak@linux.intel.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs